And james kelleher



Jan. 31, 1928. 1,657,671

F. A. J. FITZ GERALD ET AL ELECTRIC FURNACE TERMINAL Original Filed June 10. 19 2 Sheets-Sheet l Suva "tot Y m A J Ti Q M \i M 35 0 a t megs Jan. 31, 1928. 1,657,671

' F. A. J. FITZ GERALD ET AL ELECTRIC FURNACE TERMINAL Original File June 10, 1925 2 Sheets-Sheet 2 fizzy. a r

Patented Jan. 31, 1928.

. UNITED STATES PATENT OFFICE.

FRANoIsa. rr'rz GERALD, or NIAGARA. FALLS,'NEW YORK, AND JAMES KELLEHER, or CHIPPA A; oNTa Io, CANADA, ASSIGNORS T0 HARPER ELECTRIC FURNACE CORPORATION, A CORPORATION or NEW YORK.

ELECT RIC FURNACE TERMINAL.

Original application filed J1me 10, 1925, Serial No. 36,086.- Divided and this application filed March 26, a .1926. g;Serial No. 91,500, f

A This turnaces to be heated by electric'reslstors ,-I n i ts'p, je-.

ferred embodiment it relates to furnace of{ this character wherein-the resistolef is:located in :achamber ;whichis.'. seal ed from the ,out-' side'mtmosphere'sa as [to prevent access of air'tfo the heated 1 resistor..--- ;;'v or; 9 1;; r

Among the objects of our invention as to. provide means whereby current may be con-- ducted through-the ;wall of the chamber to the resistor without danger. otgaslea'kage between the chamber and the outside atmosphere. A further object is to provide-animprovedresistor terminal 1 which extends through the-wall of-the v=chamber and -is sealed thereto. A further Objectistomro vide an improved resistor terminal which" is formed and sealed in the wall ofthe resistor.

chamber,- in'such'wmanner, thatlos's-of heat from the chamberbycoriduction' out through thetern'iinahi's reduced to a minimum A further object is to provide an improved resistor terminal which is simple and economical in construction, strong and durable, an d which may be employed as a support'ior the resistor. A further object is to provide a resistor terminal having an {improved means for coolingthe same so as to prevent injury due to overheating.

Other objects and advantages of'our invention will appear from the following de scription taken in' connection with the accompanying-drawing, wherein Fig. 1 isa detailed elevation, partlyin section, showing a portion 'of the walls of the heating chamber of a furnace, a'portionof a resistor located therein'and-a conducting terminal secured to the resistor and passing through wwall of the 'cha'n'iber."

2 is a detailed elevation of a portion of the structure shown in Fig. 1, showi ng a slight modification.

Fig. 3 is asectional viewtaken' onthe line a e of Fig. 2.

Fig. 4 is a view similar to Fig. 2, but showing a still further modification.

Fig. 5=is asectional view taken on the line 55 of Fig. 4.

Fig. 6 is a side elevation of another form of ,termi nahshowing an improved means of securing'the resistor thereto.

1 Fig] is; a top plan view of the structure shown' iii Fjg fiuf r 8 is an elevation of theouter end of the terminal shown in Fig 7. Fig. 9 is a section taken on the line 9-9 of G.. showing a portion of the .resistor in elevation, 1 r

In electric furnaces of the resistance type it. is often desirable to use a terminal having diife'rent cross section and shape through its length. 'These terminals are often formed of Acheson graphite or some other form of carbon. When the portion of the terminal inside the turnace-has to be larger due'to-meohanicahnecessity, than actually required for carrying current, the cost of making these terminals out of large blocks of graphite, becomesgreat. The heat loss is also greater'through a large heavy terminal. In the forms of terminals shown in Figs. 1 to 5, we have provided an improved construction whereby theterminals may be made of two or more differently-shaped pieces, such pieces giving the desired mechanical design, good electrical properties, and permitting easy water-cooling facilities, which are generally necessarywto prevent oxidation of the terminal.

- Referring to Fig.1, the resistor 13 is adaptedt-o be supported on a resistor-carry ing block 75 of squared cross section, which in'turn-is connected, both mechanically and electrically, to the cylindrical portion 76 of the terminal by means of a threaded tapered extension 77 formed on the cylindrical portion 76 and which fits into a threaded recess in the resistor-carrying block 75. This joint, although mechanically and electrically good. is still a poor conductor of heat and serves to prevent-considerable heat loss from the resistor 13'. This joint, may, if desired, be formedas shown in Figs. 2 and 3,'wherein the cylindrical member 76 carries a tapered lug 80 adapted to be seated in a recessin the resistor-carrying block, and the two portions held together with carbonaceous half pins 81.

In case it is desired to form the in Fig. L and lead or other easily cast -metal; poured around it so as to make good heatinn; Contact between portion 76 and the coil 85. \Yater enters this coil at 88 'and leaves it at 89. Eiectrical connection with the portion--76 may-heina'de' at 90 -by"'soinefs 1itable means. The lead surrounding thecil 85 may have its outer surface cast to any shape If the -crbs's section of the-copper 85 is made sutliciently large, the tutrnflie qu'ir'cd' by' th'e-re'sisto'r 13 be izo'iidubted through pipes 85 to the terminal portion 76. This permits an even shorter "terminal and also allowsthe whole to =be' bedded solidly' in 'thehriclm'ork and elimin'atesthe neicessity of th'eelectrical connection 90.

In Figs. Gto-9,"we ha ve "sliown another form of terminal which-is providedwith' an improved means'iorse'ciiring the resistor thereto and wlnch isjfurther provided with cooling mea'ns'nnd means wh'rebyan inert gas may be supplied toiheresistonchamber through the body of thete'rminal. This terminalconsists of Acheson graphite or some other carbonaceous material and is provided near its inner end-with aninner pocket or' space 1 0 into-which the end of the resistor 13 (its? A-coil f pipe 102 designed-to'carry water oi-otliercooling medimnisse'a'ted in a deep slot orcavit 103 cut or moulded into rh tvrrninal. The cooling medium circulat ed in the pipe 10? serves to keep that: part, of the terminal which "is subjected to'the oxidizing cticct-sof gases or material below a temperature where oxidation occurs; That, pa rt'of-the slc-t103 whiclris' not-filled .withthe pipe is packed-with some good iheat 'con ducting materialsuch as -graphite.=p0 der. or it may he filled with'meta'l'su'chas lead; ctc..

'lhc 'long'narrow passage 105 .is"drilled, built-or moulded intothe terminal and has an-outlet 106 whicln-when the terminal is huilt-into'the lciln .-is inside tlie chamber on which the resistor is located' and an-in'let 107 opening outside of the-kiln. This passage is employed to supply an inert) gas or vapor to -the' rcsistor chamber. The passage 105 may .=if desired, be lined-with some hard inertsubstanee. such as porcelain. glass or other n'iaterial to prevent erosion of the terminal by the rapidly moving gases.

As stated, the resistor 13 is seated in the recess or pocket 100 of the terminal and in ord'erto permitlhe placingand removing of this resistor in an easy manner. we pro vide aremovable plate 110 of th. same inaterial' as thew-terminal, .u'hich :isadaptcd t :be seated-in bevelled or dovetailed grooves formed in: theiside-avals of the recess 100. As shown in Fig. 9, a wall 111 is left at one v.side'ofitlnreeczass 100. When it is desired to place a new resistor "in -the terminal; plane -110 is =-'-rem'0 red; f-. the

resistoi' 'dropped into the recess 100, and the space between the end of the resistor and the terminal packed-with some such' 'materia lf-as graphiteg so. as'to make good electrical C0n-' tact-i In'pl'acing' this packing. the web or wall' llf-is of 'g zeat help and the web-also= helps td' reeniorce the 'terminal' at that part of the recessr 'Wh'en "the sides -arepacked: the plate 110 is slipped-into position'and-th'e space 112.'="'-Fi'g."9;- is packed in' :wsimihr manner with graphite? This application is -'a-'division"'of Fitz Gerzfld anrlsKellchen applicationfSer-iai No.- 36'1086', filed'Jun'e 10, 1925,for=tnnnel-'kiln.

We claim; n p

'1. An electric terminal" for'usein electric resistor "fumacesr comprisinga portion formed to" extend through andbei-sealed-into thei-wall' of-said furnacezrand a second poi-- tioniof difimntv-formgadapted to. receive and' providin'g'a circuit-- connect-ion with one end ofna resistor; said portions being joined togethen'by a connection-of high electrical and low heat conductivity.

2.:An electric; terminal for use'in -electric resistor" furnaces; comprising: a portion formed to extend-through and he sealed into the 'wa ll'of said=-furnace,--and a second portion; ofditferentform, adapted toroceire and-providing a circuit; connection -with one. end of a resist-or said portions hcing joined together 'bya carbonaceous connection- 'of high electrical and low heat conductivity.

3. An electric furnace having a wal-h-an electric terminal sealed through said walL said .tcrm-inal having a detachable: joint of high ele ctricalaand-low heat conducti iti' located atapproximately the-inner. face of said walhand .fluid circulating men as extending withinsaid wallito a pointheyonrl the centre thereof for cooling-a portion of theterminal therein.

4.1A carbonaceous electric terminal for use in electric resistor furnaces comprising a. cylindrical portion adapted to be sealed through the wall of said furnace; a rectangular portion adapted to support one end of a resistor said portions being detachably joined bya connection of high electrical and low heat conductivity.

A: terminal for electric resistor furnaces comprising a cylindrical carbonaceous member adapted to be sealed into the wall of said furnace, a rectangular carbonaceous member joined to said first-named member by a screw connection of carbonaceous material, said second-named member being located inside the furnace and being adapted to support and form electrical connection with one end of a heating resistor.

6. A terminal for electric resistor furnaces comprising a cylindrical carbonaceous member adapted to be sealed into the wall of said furnace and formed at its inner end with a tapered projection, a rectangular carbonaceous member adapted to support and form electrical connection with one end of a heating resistor and formed with a tapered recess adapted to receive the tapered projection of said cylindrical member, and carbonaceous pins securing said members together.

7. An electric furnace having a wall, a terminal passing through said wall, a pipe for conveying cooling medium surrounding said terminal in said wall, and fusible metal sealing said terminal and pipe into said wall.

8. An electric furnace having a wall, a terminal comprising a cylindrical carbonaceous member passing through said wall, a coil of pipe for conveying cool ng me dium surrounding said member in said wall, and fusible metal sealing said member and pipe into said wall whereby electric current may be supplied to said terminal through said pipe.

9. A terminal adapted to extend through the wall of an electric furnace comprising a carbonaceous block having its inner end connected to a resistor and a deep slot opening at the outer end of said block, and a pipe adapted to convey acooling medium located in said slot to cool said block.

10. A terminal adapted to evtend through the wall of an. electric furnace comprising a carbonaceous block having a deep slot opening at the outer end of said block, a pipe adapted to convey cooling medium located in said slot, and fusible metal filling the space between said pipe and the walls of said slot.

11. In an electric furnace having a wall, a terminal formed of a carbonaceous block extending through said wall and formed near its inner end with a recess opening upwardly and at one side of said block, a carbonaceous resistor having one end seated in said recess and carbonaceous packing between said end and the walls of said recess.

12. In an electric furnace having a wall, a terminal formed of a carbonaceous block extending through said wall and formed near its inner end with a recess opening up" wardly and at one side of said block a carbonaceous resistor having one end seated in said recess, carbonaceous packing between said end and the walls of said recess, a carbonaceous plate fitted into and closing the top of said recess, and carbonaceous packing between said end of the resistor and said plate.

FRANCIS A. J. FITZ GERALD. JAMES KELLEHER. 

